Wire up unused config vars found in follow-up audit pass

TRANSCODE_LOG_RETENTION was documented as trimming the daily transcode log
but never referenced — log grew unbounded. TRANSCODE_ORPHAN_AGE was shown in
--status but never used, so empty session folders were deleted immediately
instead of after the documented grace period, risking a race against ffmpeg
creating a folder just before writing its first segment.

docker_watchdog.sh's daemon-health thresholds were only hardcoded fallbacks
despite comments claiming they were master.conf-configurable, and it
referenced a heartbeat feature that was never implemented (that's owned by
watchdog_orchestrator.sh, its caller) — added the three thresholds to
master.conf for real and removed the stale heartbeat claim.

Also added the missing HOSTN_PARTNERSHIP_SERVICES_STACK block to
host.conf.template (containers.sh already read it via detect_hosts, just
never had a template entry) and corrected play_state_sync.sh's doc comment
for PLAY_SYNC_TYPES' actual default.

Transcodes/transcode_manager.sh

@@ -647,6 +647,14 @@ if [[ "$DRY_RUN" == false && "$NO_LOG" == false && -n "${TRANSCODE_DAILY_LOG:-}"
     echo "${TODAY}|${RAMDISK_USED_GB}|${FLIP_COUNT}|${RAM_SESSION_COUNT}|${SSD_SESSION_COUNT}" \
         >> "$TRANSCODE_DAILY_LOG" 2>/dev/null || true
     log "Daily log written: $TRANSCODE_DAILY_LOG"
+
+    # Trim entries older than TRANSCODE_LOG_RETENTION days
+    LOG_CUTOFF=$(date -d "${TRANSCODE_LOG_RETENTION:-90} days ago" '+%Y-%m-%d' 2>/dev/null)
+    if [[ -n "$LOG_CUTOFF" ]]; then
+        awk -F'|' -v cutoff="$LOG_CUTOFF" '$1 >= cutoff' "$TRANSCODE_DAILY_LOG" \
+            > "${TRANSCODE_DAILY_LOG}.tmp" 2>/dev/null && \
+            mv "${TRANSCODE_DAILY_LOG}.tmp" "$TRANSCODE_DAILY_LOG"
+    fi
 fi
 
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